Net
pala
ntir

I was trying to retrieve data from a WCF web service (.svc) using a WebClient HTTP invocation. The service was signed like this:

[OperationContract] [WebGet(UriTemplate = "tree/{sessionId}", ResponseFormat = WebMessageFormat.Json)] public MapData GetTree(string sessionId) { // ... implementation }

and returned a complex MapData structure.

The invocation was being performed on Silverlight 3-side, like this:

Uri serviceUri = new Uri(serviceUrl);

WebClient client = new WebClient(); client.OpenReadCompleted += new OpenReadCompletedEventHandler(client_OpenReadCompleted); client.OpenReadAsync(serviceUri);

But I was getting this error at the very beginning of the client_OpenReadCompleted function:

{System.Net.WebException: The remote server returned an error: NotFound. at XXX.client_OpenReadCompleted(Object sender, OpenReadCompletedEventArgs e) at System.Net.WebClient.OnOpenReadCompleted(OpenReadCompletedEventArgs e) at System.Net.WebClient.OpenReadOperationCompleted(Object arg)}

But the URL was correct and all was installed correctly. So what was wrong?

Solution: This was caused by the impossibility by the server to perform the serialization, because in the data structure there were reference loops. For example:

SampleObject a = new SampleObject(); SampleObject b = new SampleObject(); a.objectReference = b; b.objectReference = a; finalDataStructure.add(a); finalDataStructure.add(b); After removing such references, the service performed correctly. And since I needed them, I re-added them client-side.